This research paper contains two main purposes, to study the teachings of the Buddha found in Nandakovādasutta and to study the practical way of insight development in Nandakovādasutta. It was done by documentary method by collecting the research data from Tipitaka, its commentaries and sub-commentaries, other Visesapakarana texts concerned, then analyzed, compiled in descriptive style. Its findings are as followings;
Nandakovādasutta involves the teaching of Nandakathera delivered to Bhikkhunis. He explained the impermanence of inner and outer sensual organ bases. This discourse was grouped in Suttanta, Majjhimanikaya, salayatanavagga. Those who require wisdom on seeing the truth through Three Common Characteristics as the base of insight development which focuses on observing sensual organ bases. The main teachings in Nandakovādasutta are 6 inner organ bases, 6 outer organ bases, 4 Tilakkhana and 7 Bojjhanga which are capable to lead to Cetovimutti and Paññāvimutti.
The insight practice found in Nandakovādasutta shows that the teaching of Nandaka concerns on the process of wisdom cultivation for realizing the true nature of Nama-Rupa, Sensual Organs as falling into Three Common Characteristics through the simile of Sensual Organs of Ayatana, and realization based on 7 Bojjhanga or factors of enlightenment which is the key for insight practice therefore Vipassana is only one right way to lead to Cetovimutti and Paññāvimutti. Finally, all 500 Bhikkhunis appreciating that teaching had received the great benefits by attainment the first Noble One or Sotāpanna.